Numerous types of machines for screeding paving materials such as concrete have been developed, examples of which are shown in U.S. Pat. Nos. 1,584,385; 2,426,702; 2,687,679; 3,377,933; 4,115,976; and 4,747,726. Such machines generally comprise a frame supported by two or more rollers, at least one of which is driven, that roll on forms straddling the surface area to be paved which serve as a track or support rails for the machine. A screed roller is located forward on the frame which is slightly elevated above the support rollers and the forms. The screed roller is generally driven in a reverse direction to the support rollers so that as the machine advances through the paving material, which has been clumped between the forms, the screed roller flings and spreads the material ahead of the machine, flattening and leveling piles thereof. The support rollers then pass over the material, further flattening and smoothing it.
The screeding process as just described produces a fairly flat, even surface of paving material. However, as is often the case, where a smooth, essentially non-porous or non-pitted surface is desired, it is necessary that the operation be completed manually by means of work crews using bull floats or trowels. Immediately after screeding, the paving material, especially concrete, contains a great deal of semi-liquid "soup". Floating or troweling causes this soup to rise to the surface where it is evenly spread thus producing a smooth, relatively non-pitted surface. Such floating or troweling, while desirable for producing a smooth surface, is both time consuming and labor intensive, thus costly.
Accordingly, it is an object of the present invention to reduce materially the time and expense incident of the finish float operation.
More particularly, it is an object of the present invention to incorporate the final smoothing operation into the operation of the screeding machine, thereby substantially eliminating the labor intensive, costly floating operation.